The present invention relates to a shift control apparatus of a belt type continuously variable transmission (CVT) which is capable of steplessly changing a transmission ratio in a manner that contact radii of primary and secondary pulleys relative to an endless belt are varied by hydraulically controlling groove widths of the pulleys.
Japanese Patent No. 2813671 discloses a belt type CVT control apparatus for controlling a primary pulley hydraulic pressure and a secondary pulley hydraulic pressure of the belt type CVT. This control apparatus comprises a hydraulic pressure ratio control system and a flow rate control system, and is arranged to determine a target primary pulley hydraulic pressure from pressure values necessary for the hydraulic pressure ratio control system and a flow rate control system and to execute a shift control according to the target primary pulley pressure so as to achieve a stable shift control.